add SPDX license identifiers

xenv/__main__.py

@@ -12,6 +12,8 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 """runpy hook"""
 

xenv/cli.py

@@ -12,6 +12,8 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 """xenv program logic."""
 import configparser

xenv/modules.py

@@ -12,6 +12,8 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 """xenv's actual module load/use/purge code."""
 import ast

xenv/proc.py

@@ -12,6 +12,8 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 """xenv module for process management"""
 import subprocess